4b5r

Publication Abstract from PubMed

The k-turn is a widespread structural motif that introduces a tight kink into the helical axis of double-stranded RNA. The adenine bases of consecutive G*A pairs are directed toward the minor groove of the opposing helix, hydrogen bonding in a typical A-minor interaction. We show here that the available structures of k-turns divide into two classes, depending on whether N3 or N1 of the adenine at the 2b position accepts a hydrogen bond from the O2' at the -1n position. There is a coordinated structural change involving a number of hydrogen bonds between the two classes. We show here that Kt-7 can adopt either the N3 or N1 structures depending on environment. While it has the N1 structure in the ribosome, on engineering it into the SAM-I riboswitch, it changes to the N3 structure, resulting in a significant alteration in the trajectory of the helical arms.

The plasticity of a structural motif in RNA: Structural polymorphism of a kink turn as a function of its environment.,Daldrop P, Lilley DM RNA. 2013 Jan 16. PMID:23325110^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.